C, decrement struct 2d array pointed to by struct pointer

[mike.bauer]

I have the following struct deceleration and I would like to decrement eq->pt_tree[c][r], the row portion of pt_tree[c][r] using pointer subscript. How can I do this?

struct eq_values{
   int * pt_tree[2];
}; 
eq->pt_tree[i] = (int *) malloc(12 * sizeof (int));

I think it will look like the following, but this is not it

*(eq->pt_tree[c])--;

[deceptikon]

Try --(*eq->pt_tree[c]); .